We have developed a prostatic cancer model by systemic administration of N-nitrosobis (2-oxopropyl) amine (BOP). The high yield of preneoplastic and neoplastic lesions (over 80 percent), relatively short tumor latency (30-40 weeks) and morphologic similarities of induced early lesions to those occurring in man makes this model an ideal tool to investigate some important aspects of prostatic cancer. We are proposing experiments to improve the model by increasing the tumor yield, by shortening the tumor latency, by reducing or eleminating tumor formation in tissues other than the prostate, and by maintaining the glandular patterns of the induced tumors in advanced cases. We plan to achieve this goal by a two-phased approach. In phase I: We will investigate the status of sex hormones in carcinogen-treated rats, since data indicate alteration of these levels during carcinogenesis. This could be a reason for later squamous cell differentiation of an initially glandular type of cancer. The results of these studies will be useful in planning experiments for phase II in which we will define the enhancing effects of either estrogen or testosterone in prostatic carcinogenesis induced by BOP. Moreover, the prostatic carcinogenic effect of the assumed proximate prostatic carcinogen N-nitrosomethyl-(2-oxopropyl) amine (MOP), formed from BOP, will be investigated. Furthermore, we propose to use a rat strain with a high incidence of spontaneous prostatic cancer and these animals will be treated with BOP.